What Is Petroleum Pitch?

5 What Is Petroleum Pitch? JOHN W. NEWMAN

Downloaded by UNIV OF MICHIGAN ANN ARBOR on September 24, 2015 | http://pubs.acs.org Publication Date: June 1, 1976 | doi: 10.1021/bk-1976-0021.ch005

Research and Development Department, Ashland Petroleum Co., Ashland, Ky. 41101

The term petroleum pitch can have many definitions, and the most general is pitch derived from petroleum. What, then, i s pitch? Pitch can be defined as thick, dark colored bituminous substances obtained as a result of industrial destructive d i s t i l l a t i o n processes, obtained as deposits on the earth surface, or, of primary interest here, manufactured from a specially selected feedstock. Natural pitch was known to the ancients and Noah probably used it to calk the ark. Wood tars were widely used to calk the early sailing vessels. The earliest reference to the p o s s i b i l i t y of commercial recovery of tar from coal appeared i n B r i t i s h Patent No. 214 issued i n 1681 to Beker and Surley. At this time, no attempt was made to commercialize the process as ample supplies of wood tar were available. During the American Revolution, however, Great Britain could not depend on the American colonies to supply her wood tar requirements and interest was revived i n the use of coal tar as a wood tar substitute. In 1781, B r i t i s h Patent No. 1291 was granted to Archibald Cochran on a method of extracting or making tar pitch, essential o i l s , v o l a t i l e a l k a l i , mineral acids, salts and cinders from p i t coal. Since World War I I , many of the same or related coal tar products have become increasingly available from petroleum and pitch i s no exception. The patent literature (1, 2, 3) contains numerous examples of petroleum pitch manufacturing processes· Examples of feedstocks that could be used to produce a petroleum derived pitch include decant o i l from a f l u i d catalytic cracking unit, byproduct aromatic extracts from lube o i l processes, asphaltic residues from vacuum s t i l l s , hard asphalt from solvent deasphalting units, and the tar-like bottoms from the pyrolysis of naphtha and gas o i l s for the manufacture of ethylene. Obviously, there can be many petroleum pitches, each quite different from another. Examples of three different petroleum pitch processes, taken from the patent l i t e r a t u r e , and using decant o i l as feedstock are summarized i n Figures 1 through 8. The differences i n physical properties among two different petroleum pitches and a coal tar pitch 52

In Petroleum Derived Carbons; Deviney, M., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1976.

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NEWMAN

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Petroleum Pitch GAS


GASOLINE F R A C Τ I Ο Ν A Τ Ο R

NAPHTHA

KEROSENE

k

FURNACE OIL

Figure 1. Petroleum pitch manufacture— crude oil fractionation

CRACKED PRODUCT TO

HEAVY CYCLE O I L LIGHT CYCLE O I L

500-1100*7 B P FCC CHARGE

" " CATALYST

•OIL

Figure 2. Petroleum pitch manufacture—fluid catalytic cracking


PETROLEUM DERIVED CARBONS


GASOLINE

CRACKED PRODUCT FROM FLUID REACTOR

FURNACE OIL

CLARIFIED CYCLE OIL OR DECANT OIL, FEEDSTOCK FOR PITCH PRODUCTION

LIGHT CYCLE OIL

RECYCLE STREAMS TO FLUID ~ REACTOR XZ

Figure 3. Petroleum pitch manufacture-^production of pitch feedstock

_^ RAFFINATE

o4o

o4o

(DECANT OIL) DECANT OIL EXTRACT

Figure 4. Petroleum pitch manufacture—concentration of aromatics by solvent extraction


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Petroleum Pitch

NEWMAN

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GAS

1

i


THERMAL CRACKING HEATER

CLARIFIED SLURRY OIL

1

(DECANT OIL)

400-1000*F FRACTION

Τ

TO SOAKING FURNACE

Figure 5. Petroleum pitch manufacture—thermal process, initial step

GAS OIL

GAS

SOAKING FURNACE

FRACTIONATOR BOTTOMS ~ *

Τ

PITCH PRODUCT

Figure 6. Petroleum pitch manufacture—thermal process, final step



Figure 8. Petroleum pitch manufacture—combination of thermal and oxidation routes



Figure 10. Comparison of thermal stability—fiber pipe impregnantnominal 170°F S/P (R and B)



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Τ Ι 0 ,

MINUTES

Figure 11. Comparison of cold flow properties commercially avaifoble fiber pipe im nants—grease cone penetrometer, 200 g load, 77° F

Figure 12.Comparison of Brookfield viscosity—petroleum and coal tar high softening point pitch



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Petroleum Pitch

TABLE 1 COMPARISON OF TYPICAL PROPERTIES - ASHLAND PETROLEUM PITCHES

Test Method Softening Point, °F (ASTM D 2398) Softening Point, °C (ASTM D 3104) Coking Value, % (ASTM D 2416) Quinoline Insolubles, % (ASTM D 2318) Benzene Insolubles, % (ASTM D 2317) Specific Gravity (ASTM D 2320) Ash, % (ASTM D 2415) Sulfur, % (LECO) Brookfield Viscosity, cps, 350°F 375°F 400°F 425°F 450°F

Ashland 170 Pitch

Ashland 240 Pitch

Ashland Purified Carbon Precursor

170 81 36.3 Nil 3.5 1.185 0.1 2.8

240 120 50.3 Nil 5.5 1.228 0.1 2.8

240 120 50.4 Nil 2.5 1.210 0.02 0.25

35 _ _ _ _

395 180 88 50 31

315 178 88 48 30




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that are commercially available to the fiber pipe industry are shown graphically i n Figures 9 through 11. A graph comparing the viscosity-temperature relationship of two different types of petroleum pitch and a coal tar pitch that are typical of electrode binder pitches i s shown i n Figure 12· In the early 1960*8, Ashland Petroleum Company began to experiment with different petroleum pitch manufacturing processes in their Research & Development laboratory. It soon became evident that there was a place i n the market for a high quality, consistent, manufactured petroleum pitch as opposed to pitches which were simply by-products or inconsistently manufactured by batch processes. By the mid 1960*8, Ashland had developed a proprietary commercial, petroleum pitch manufacturing process. The electrode binder pitch produced by this process became the f i r s t commercial petroleum pitch to be f u l l y approved as an électrode binder pitch by a major U.S. aluminum company (4, 5) . Ashland petroleum pitch was introduced into the specialty graphite area through the Nerva Program and i s now being used by the country's leading specialty graphite companies as a high quality carbon precursor for graphites and graphite and carbon fibers (6,7,8,9,10, 11.12 J3.14 J.5,16,17 ,18»19 ,20,21,22,23,24) . Typical laboratory inspections of plant produced A-240 grade electrode binder and A-170 grade fiber pipe impregnating petroleum pitch (25) and a new high purity carbon precursor produced from a new p i l o t unit are shown i n Table 1. The purifie d carbon precursor now available in drum quantities from Ashland Petroleum Company was developed in response to a request from the specialty carbon industry for a consistent, high purity petroleum pitch. What i s petroleum pitch? Petroleum pitch can be an inconsistent ,low quality, black carbonaceous mass derived from petroleum, or i t can be a consistent, high quality carbon precursor manufactured to specification from selected hydrocarbon feedstocks . Literature Cited 1. 2. 3. 4.

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B e l l , J . F., et al., "Process for Preparing Binder Pitches," U.S. Patent 3,140,248, July 7, 1964. Baum, L. Α. Η., "Process for Producing Electrode Binder Asphalt," U.S. Patent 3,725,240, A p r i l 3, 1973. Alexander, S. H., et al., "Production of Petroleum Base Pitch and Aromatic Oils," U.S. Patent 3,318,801, May 9, 1967. Alexander, C. D., et al., "Laboratory and Plant Performance of Petroleum Pitch," AIME Paper No. A71-29, AIME and WAAIME 100th Annual Meeting, New York C i t y , February 1971, Published by AIME, 345 East 47th Street, New York, New York 10017. B a l l , G. L., et al., "Petroleum Pitch - A Major New Carbon Source," Proceedings of Sessions-101st AIME Annual Meeting, San Francisco, California, February 1972, Published by AIME, 345 East 47th Street, New York, New York 10017.



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Petroleum Pitch

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6. Smith, W. Ε., et al., "Characterization and Reproducibility of Petroleum Pitches," Oak Ridge Y-12 Plant, Published by U.S. Department of Commerce, Report No. Y-1921. 7. Overholser, L. G., "Nerva Fuel Element Development Program Summary Report-July 1966 through June 1972, Oak Ridge Y-12 Plant, Published by U.S. Department of Commerce, Report No. Y-1857. 8. Horne, O. J . , etal.,"Properties of Carbon Derived from Petroleum Pitches," Oak Ridge Y-12 plant, Published by U.S. Department of Commerce, Report No. Y-1875. 9. Netherlands Patent Application 73-04398, "Process for Prepara tion of Carbon Fibers from Pitch i n the Mesophase State with a High Modulus of E l a s t i c i t y and a Great Strength," Date open to Inspection October 2, 1973. 10. Newman, J . W., "Petroleum Pitch - A Consistent Carbon Pre cursor," 11th Biennial Conference on Carbon, Extended Abstracts, 1973, p. 104, Published by NTIS, U.S. Department of Commerce, Springfield, Virginia 22151. 11. Jones, S. S. and Hildebrandt, R. D., "Reactivity of Selected Carbons with Oxygen and Carbon Dioxide," 11th Biennial Con ference on Carbon Abstracts, p. 84. 12. Smith, W. E., "Structural Characterization of Petroleum Derived Carbon Precursors," 11th Biennial Conference on Carbon Abstracts, p. 106. 13. Whittaker, M. P., and M i l l e r , F. C., "Unique Binder Systems for the Fabrication of Graphite," 11th Biennial Conference on Carbon Abstracts, p. 110. 14. Kennedy, C. R. and Eatherly, W. P., "The Development of Thermal Shock Resistant Graphite," 11th Biennial Conference on Carbon Abstracts, p. 131. 15. Gilliam, H. G., and Whittaker, M. P., "Mesophase Graphite," 11th Biennial Conference on Carbon Abstracts, p. 211. 16. Bradley, R. Α., and Sease, J . D., "The Slug Injection Process for Fabricating HTGR Fuel Rods," 11th Biennial Conference on Carbon Abstracts, p. 239. 17. Hamner, R. L., etal.,"Development of Continuous-Matrix Fuel Rods for Advanced HTGR," 11th Biennial Conference on Carbon Abstracts, p. 259. 18. Kennedy, C. R., and Eatherly, W. P., "Development of Graphites for Resistance to Irradiation Damage," 11th Biennial Confer ence on Carbon Abstracts, p. 304. 19. Kennedy, C. R., "Irradiation of Graphite at 950°C," 11th Biennial Conference on Carbon Abstracts, p. 312. 20. White, J . L., etal.,"Mechanisms of Formation of Needle Coke," 12th Biennial Conference on Carbon Extended Abstracts, 1975, p. 221. 21. Rester, D, O., "Factors Controlling the Mesophase Microstruc ture Produced During Pyrolysis of Aromatic Hydrocarbons," 12th Biennial Conference on Carbon Extended Abstracts, 1975, p.227.



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22. Horne, O. J . and Kennedy, C. R., "Graphites Fabricate d From Green Petroleum Pitch Cokes," 12th Biennial Conference on Carbon Extended Abstracts, 1975, pp. 255-256. 23. Lewis, I. C. and Jackson, G. W., "Heat of Reaction for Mesophase Formation," 12th Biennial Conference on Carbon Extended Abstracts, 1975, pp. 267-268. 24. Didchenko, R., et al., "High Modulus Carbon Fibers From Mesophase Pitches, Parts One and Two," 12th Biennial Conference on Carbon Extended Abstracts, 1975, pp. 329-332. 25. Gannon, C. R., Australian Patent Number 451,613, Pending i n U.S.A., Impregnated A r t i c l e s , Method for Making Same, and Impregnant Composition.


What Is Petroleum Pitch?

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